Be sure to list the subject and what story you would like told. Is this about a person? An event? A location? What are your goals? Remember to preempt any questions and give examples of videos that you would like to see.
Be open to pre-production, but give as much info on the shoot date, the amount of videos and if the price is negotiable. Talk about what you would like to see and who the audience will be. Remember, the more info given, the better.